1. Field of the Invention
The present invention relates to an apparatus (finisher) for bundling sheets sent from an image forming apparatus, thereby carrying out, for example, staple processing and a waiting tray for use in the post-process apparatus.
2. Description of the Related Art
A post-process apparatus comprises: a processing tray for bundling sheets sent from an image forming apparatus, thereby carrying out, for example, staple processing, and ejecting the processed bundles of sheets; and a storage tray for holding the ejected bundles of sheets. A staple processing speed of the post-process apparatus is slow as compared with an image processing speed of the image forming apparatus. Thus, if a sheet is directly sent to the processing tray, a sheet to be staple processed next is transported while a preceding sheet is staple processed. In order to prevent this problem, conventionally, a buffer mechanism for adjusting a carrying-in timing of a sheet at a front stage of the processing tray is proposed.
Japanese Patent Document 1: Japanese Patent No. 2583594 discloses a mechanism for retaining sheets is provided at a transport passage for sending sheets sent from an image forming apparatus to a processing tray. However, in this case, there is a need for increasing the transport passage in length, and, as a result, the post-process apparatus is likely to be large in size.
Japanese Patent Document 2: Jpn. Pat. Appln. KOKAI Publication No. 11-322162 discloses a mechanism configured to provide a paddle on a staple tray for temporarily holding a sheet so as to be substantially constantly maintain a contact pressure of the paddle with respect to a sheet at the top level ejected on the tray. This mechanism prevents excessive return of the sheet due to a change of a contact area of pulling means with respect to the sheet at the top level. This mechanism is technically different from that of the present invention, and advantageous effect of the present invention cannot be attained by this mechanism.